If he keeps doing that, maybe think about filing some kind of sexual harassment complaint? Sounds like it's unwelcome or is at the very least making you feel uncomfortable, and if it's coming from your boss, it's harassment regardless of how you feel about it.

I dunno, I think that was a mistake. Gettin some sex is a great way to start off the weekend. And then I'm sure you could have at least got a raise or a promotion out of it. Or video tape it and use it as blackmail. Just another card up your sleeve in case you need to play it